Field of the Disclosure
The disclosure relates to a method for forming 2,5-furan dicarboxylic acid (FDCA) from aldaric acids. The aldaric acids are dehydrating and cyclizing via acid catalysis to form the FDCA product. The aldaric acids can be obtained from renewable biomass sources which contain pectin, alginate, and/or other biomass carbohydrates. The FDCA can be used as a feedstock for polyalkylene furoate polymers.
Background
Most current effort toward producing FDCA is centered around a chemical pathway involving the dehydration of glucose or (more easily) fructose to form hydroxymethyl furfural (HMF), which is then oxidized to FDCA by a variety of catalysts. There are two challenges with this route at present: one is that the intermediate HMF is a difficult molecule to isolate, because it has low volatility and low decomposition temperature. The second is that the oxidation of HMF to FDCA is not particularly efficient and requires precious metal catalysts, dilute reaction conditions, and control of pH. Because of these challenges, no commercial production of FDCA from HMF exists at present.
Another approach is the formation of FDCA esters from galactaric acid. Specifically, dibutyl FDCA ester from butyl galactarate was formed via the action of sulfuric acid in butanol solvent; this reaction proceeded readily but was accompanied by the formation of dibutyl sulfate which eventually consumed the sulfuric acid and quenched the reaction.